The present invention relates to a sliding mechanism having excellent low-friction characteristics, particularly of the kind for use in an internal combustion engine, a drive train or a hard disk drive.
Global environmental problems such as global warming and ozone layer destruction are coming to the fore. As it is said that the global warming is significantly effected by CO2 emission, the reduction of CO2 emission, notably the setting of CO2 emission standards, has become a big concern to each country.
One of challenges to reduce CO2 emission is to improve vehicle fuel efficiency that depends on the performance of engine sliding members and a lubricant applied thereto. There are the following approaches to improving vehicle fuel efficiency: (1) to provide higher abrasion resistance and a lower friction coefficient for the sliding members, which are generally made of steel materials in the earlier technology, even under extreme conditions of abrasion and friction; (2) to lower the viscosity of the lubricant, thereby reducing viscous resistance in hydrodynamic lubrication regions and agitation resistance in the engine; and (3) to mix a suitable friction modifier and other additives into the lubricant so as to reduce friction losses under the conditions of mixed lubrication and boundary lubrication.
In view of the foregoing, many studies have been made on various friction modifiers including organomolybdenum compounds, such as molybdenum dithiocarbamate (MoDTC) and molybdenum dithiophosphate (MoDTP). As a result of the studies, it is found that the lubricant containing an organomolybdenum compound successfully produces a friction reducing effect on the steel sliding members in the early stages of use.